OpenSubdiv/opensubdiv/osd/mtlPatchGregory.metal
David G Yu 67cc2a3810 Irregular patch shader transition edges
Updated the Gregory patch tessellation shaders to account for
transition edges.

Changed the implementation of OsdGetTessParameterizationTriangle()
to take the input parametric location as a 3-component value. This
allows the edge parameterization to be more numerically robust and
consistent.

Also, corrected some minor discrepancies between the various
tessellation shader configurations.
2019-06-03 15:34:40 -07:00

278 lines
8.2 KiB
Metal

#line 0 "osd/mtlPatchGregory.metal"
//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
//----------------------------------------------------------
// Patches.Gregory.Hull
//----------------------------------------------------------
void OsdComputePerVertex(
float4 position,
threadgroup OsdPerVertexGregory& hullVertex,
int vertexId,
float4x4 modelViewProjectionMatrix,
OsdPatchParamBufferSet osdBuffers
)
{
OsdComputePerVertexGregory(vertexId, position.xyz, hullVertex, osdBuffers);
#if OSD_ENABLE_PATCH_CULL
float4 clipPos = mul(modelViewProjectionMatrix, position);
short3 clip0 = short3(clipPos.x < clipPos.w,
clipPos.y < clipPos.w,
clipPos.z < clipPos.w);
short3 clip1 = short3(clipPos.x > -clipPos.w,
clipPos.y > -clipPos.w,
clipPos.z > -clipPos.w);
hullVertex.clipFlag = short3(clip0) + 2*short3(clip1);
#endif
}
//----------------------------------------------------------
// Patches.Gregory.Factors
//----------------------------------------------------------
void OsdComputePerPatchGregoryFactors(
int3 patchParam,
float tessLevel,
float4x4 projectionMatrix,
float4x4 modelViewMatrix,
device OsdPerPatchVertexGregory* patchVertices,
#if !USE_PTVS_FACTORS
device OsdPerPatchTessFactors& patchFactors,
#endif
device MTLQuadTessellationFactorsHalf& quadFactors
)
{
float4 tessLevelOuter = float4(0);
float2 tessLevelInner = float2(0);
float4 tessOuterLo = float4(0);
float4 tessOuterHi = float4(0);
#if OSD_ENABLE_SCREENSPACE_TESSELLATION
// Gather bezier control points to compute limit surface tess levels
float3 bezcv[16];
bezcv[ 0] = patchVertices[0].P;
bezcv[ 1] = patchVertices[0].Ep;
bezcv[ 2] = patchVertices[1].Em;
bezcv[ 3] = patchVertices[1].P;
bezcv[ 4] = patchVertices[0].Em;
bezcv[ 5] = patchVertices[0].Fp;
bezcv[ 6] = patchVertices[1].Fm;
bezcv[ 7] = patchVertices[1].Ep;
bezcv[ 8] = patchVertices[3].Ep;
bezcv[ 9] = patchVertices[3].Fm;
bezcv[10] = patchVertices[2].Fp;
bezcv[11] = patchVertices[2].Em;
bezcv[12] = patchVertices[3].P;
bezcv[13] = patchVertices[3].Em;
bezcv[14] = patchVertices[2].Ep;
bezcv[15] = patchVertices[2].P;
OsdEvalPatchBezierTessLevels(
tessLevel,
projectionMatrix,
modelViewMatrix,
bezcv,
patchParam,
tessLevelOuter,
tessLevelInner,
tessOuterLo,
tessOuterHi
);
#else
OsdGetTessLevelsUniform(
tessLevel,
patchParam,
tessLevelOuter,
tessLevelInner,
tessOuterLo,
tessOuterHi
);
#endif
quadFactors.edgeTessellationFactor[0] = tessLevelOuter[0];
quadFactors.edgeTessellationFactor[1] = tessLevelOuter[1];
quadFactors.edgeTessellationFactor[2] = tessLevelOuter[2];
quadFactors.edgeTessellationFactor[3] = tessLevelOuter[3];
quadFactors.insideTessellationFactor[0] = tessLevelInner[0];
quadFactors.insideTessellationFactor[1] = tessLevelInner[1];
#if !USE_PTVS_FACTORS
patchFactors.tessOuterLo = tessOuterLo;
patchFactors.tessOuterHi = tessOuterHi;
#endif
}
void OsdComputePerPatchFactors(
int3 patchParam,
float tessLevel,
unsigned patchID,
float4x4 projectionMatrix,
float4x4 modelViewMatrix,
OsdPatchParamBufferSet osdBuffer,
threadgroup PatchVertexType* patchVertices,
device MTLQuadTessellationFactorsHalf& quadFactors
)
{
OsdComputePerPatchGregoryFactors(
patchParam,
tessLevel,
projectionMatrix,
modelViewMatrix,
osdBuffer.perPatchVertexBuffer + patchID * VERTEX_CONTROL_POINTS_PER_PATCH,
#if !USE_PTVS_FACTORS
osdBuffer.patchTessBuffer[patchID],
#endif
quadFactors
);
}
//----------------------------------------------------------
// Patches.Gregory.Vertex
//----------------------------------------------------------
void OsdComputePerPatchVertex(
int3 patchParam,
unsigned ID,
unsigned PrimitiveID,
unsigned ControlID,
threadgroup PatchVertexType* patchVertices,
OsdPatchParamBufferSet osdBuffers
)
{
OsdComputePerPatchVertexGregory(
patchParam,
ID,
PrimitiveID,
patchVertices,
osdBuffers.perPatchVertexBuffer[ControlID],
osdBuffers);
}
//----------------------------------------------------------
// Patches.Gregory.Domain
//----------------------------------------------------------
template<typename PerPatchVertexGregory>
OsdPatchVertex ds_gregory_patches(
const float tessLevel,
#if !USE_PTVS_FACTORS
float4 tessOuterLo,
float4 tessOuterHi,
#endif
PerPatchVertexGregory patch,
int3 patchParam,
float2 domainCoord
)
{
float3 cv[20];
cv[0] = patch[0].P;
cv[1] = patch[0].Ep;
cv[2] = patch[0].Em;
cv[3] = patch[0].Fp;
cv[4] = patch[0].Fm;
cv[5] = patch[1].P;
cv[6] = patch[1].Ep;
cv[7] = patch[1].Em;
cv[8] = patch[1].Fp;
cv[9] = patch[1].Fm;
cv[10] = patch[2].P;
cv[11] = patch[2].Ep;
cv[12] = patch[2].Em;
cv[13] = patch[2].Fp;
cv[14] = patch[2].Fm;
cv[15] = patch[3].P;
cv[16] = patch[3].Ep;
cv[17] = patch[3].Em;
cv[18] = patch[3].Fp;
cv[19] = patch[3].Fm;
#if USE_PTVS_FACTORS
float4 tessOuterLo(0), tessOuterHi(0);
OsdGetTessLevelsUniform(tessLevel, patchParam, tessOuterLo, tessOuterHi);
#endif
float2 UV = OsdGetTessParameterization(domainCoord,
tessOuterLo,
tessOuterHi);
OsdPatchVertex output;
float3 P = float3(0), dPu = float3(0), dPv = float3(0);
float3 N = float3(0), dNu = float3(0), dNv = float3(0);
OsdEvalPatchGregory(patchParam, UV, cv, P, dPu, dPv, N, dNu, dNv);
// all code below here is client code
output.position = P;
output.normal = N;
output.tangent = dPu;
output.bitangent = dPv;
#if OSD_COMPUTE_NORMAL_DERIVATIVES
output.Nu = dNu;
output.Nv = dNv;
#endif
output.tessCoord = UV;
output.patchCoord = OsdInterpolatePatchCoord(UV, patchParam);
return output;
}
#if USE_STAGE_IN
template<typename PerPatchVertexGregoryBasis>
#endif
OsdPatchVertex OsdComputePatch(
float tessLevel,
float2 domainCoord,
unsigned patchID,
#if USE_STAGE_IN
PerPatchVertexGregoryBasis osdPatch
#else
OsdVertexBufferSet osdBuffers
#endif
)
{
return ds_gregory_patches(
tessLevel,
#if !USE_PTVS_FACTORS
#if USE_STAGE_IN
osdPatch.tessOuterLo,
osdPatch.tessOuterHi,
#else
osdBuffers.patchTessBuffer[patchID].tessOuterLo,
osdBuffers.patchTessBuffer[patchID].tessOuterHi,
#endif
#endif
#if USE_STAGE_IN
osdPatch.cv,
osdPatch.patchParam,
#else
osdBuffers.perPatchVertexBuffer + patchID * VERTEX_CONTROL_POINTS_PER_PATCH,
osdBuffers.patchParamBuffer[patchID],
#endif
domainCoord);
}